Dunbar Distribution markets CDs of numerous performing artists. At the beginning of March, Dunbar had in beginning inventory 3,723 CDs with a unit cost of $10. During March, Dunbar made the following purchases of CDs. March 5 2,978 @ $12 March 21 7,445 @ $15 March 13 5,212 @ $13 March 26 2,978 @ $16 During March 17,868 units were sold. Dunbar uses a periodic inventory system